I think semantic coloring (based on structure) is more useful. Also (can't help as someone working with z/OS), if you really want to make hex output readable, I recommend using big-endian machine.

I've started doing this with hashes in a CLI I'm working on. For slow prints, it's somewhat helpful https://asciinema.org/a/aD38Pk88CZgSZqtq but for debug dumps with many many hashes it really helps readability and tracking hashes across lines.

Emacs's hexl-mode does this, incidentally, though annoyingly by default it makes all faces the same color. I never understood why it defines the faces but then doesn't customize them.